In a universe as vast as it is mysterious, a small but powerful force has existed for centuries. Protectors of peace and justice, they are called the Green Lantern Corps. A brotherhood of warriors sworn to keep intergalactic order, each Green Lantern wears a ring that grants him superpowers. But when a new enemy called Parallax threatens to destroy the balance of power in the Universe, their fate and the fate of Earth lie in the hands of their newest recruit, the first human ever selected: Hal Jordan.

Hal (Ryan Reynolds) is a gifted and cocky test pilot, but the Green Lanterns have little respect for humans, who have never harnessed the infinite powers of the ring before. But Hal is clearly the missing piece to the puzzle, and along with his determination and willpower, he has one thing no member of the Corps has ever had: humanity. With the encouragement of fellow pilot and childhood sweetheart Carol Ferris (Blake Lively), if Hal can quickly master his new powers and find the courage to overcome his fears, he may prove to be not only the key to defeating Parallaxâ€¦he will become the greatest Green Lantern of all.

We sat down last weekend at Comic Con with Ryan Reynolds, Blake Lively, Peter Sarsgaard, Mark Strong, director Martin Campbell and producer Donald De Line to talk about their exciting new film. They talked to us about their characters, the casting/audition process and their training for the action sequences. Here’s what they had to say about their upcoming action/sci-fi adventure which is scheduled for release in June 2011:

Q: Is Green Lantern a hard sell for audiences simply because there’s so much going on?

Martin Campbell: It’s not a tough one to explain. I think it’s all very, very clear. I think the story that we are telling, which is the Hal Jordon story, is quite concise actually -- the fact that he is taken up to Oa and he’s inducted and he becomes a Green Lantern and the way in which the ring works through willpower. The stronger your willpower, the stronger your construct -- construct being whatever your imagination cares to create. The actual story is very simple. I know there are many complex characters and all the characters from the origin story go on to the dark side in later comics and things, but I think it’s very straightforward.

Q: For Ryan, are there any specific Green Lantern comic book storylines that you’re particularly fond of?

Ryan Reynolds: There’s a lot of them that are inspiring. Unlike many of the comic books, it’s such a vast universe to this character and his contemporaries. I read a few different ones. For the most part, this is an origin story, so I was able to focus a little on Secret Origins, but then, obviously, our script is a much more in-depth interpretation of that basic storyline. Geoff Johns described this thing as a version of Star Wars in the DC universe. I think that was a pretty apt description. You have so much you can mine out of this -- out of these comics and this character in particular. I think that any time you’re dealing with a guy who has something unbelievable and insurmountable to overcome, it makes for a pretty interesting story. As an actor, it’s an interesting and excellent thing for me to get an opportunity to play. This guy has a very distinct starting point. He’s a bit of a fractured human being. He’s seen some difficult stuff in his life. He’s seen his father die. We move on to find him a little bit later in life and he’s kind of arrogant, cocky and aimless. It’s this extraordinary power that is bestowed on him that sort of sets him on a bit of a humbler path. It’s pretty cool.

Q: How does your experience playing a superhero in Green Lantern differ from playing the imaginary superhero in Paper Man? And is this costume even tighter than the Paper Man costume?

Ryan Reynolds: So you’re the guy that saw Paper Man! Yeah, this costume is a motion capture suit that I’m wearing. Because it’s not seen on camera, they’ve managed to find a material that I think most would agree is the most aggravating substance on earth. We’re shooting in Louisiana, which is pretty close to the sun in terms of the hottest place you can find anywhere around. The suit has actually been a little bit difficult running around in a unitard in the New Orleans high summer heat. If I were wearing anything, it’s going to be pretty uncomfortable doing an action movie this time of year in the Deep South. I can’t be too hard on the suit.

Q: You’ve done a lot of training for action scenes in the past, but how much more extensive is the training for the aerial sequences we’ve been hearing about?

Ryan Reynolds: The training’s just different. You’re not training on an aesthetic level, you’re training for more of a functional ability. You want to be able to stay out of the hospital for as long as you possibly can. But it is a Martin Campbell movie, so you’re bound to be there once or twice. He pushes you so hard and I think that’s why the action is so real and so visceral. You really feel what Martin once described as a knife fight in a phone booth. I think that’s a really apt description of how his action feels. It’s rough. It’s dirty. It’s fast. You’ve got to be ready for it. It’s been fun to train in that regard for something actually real.

Q: Blake, did you have to do any special training to play Carol Ferris?

Blake Lively: I had to spend many days with Ryan. That was my training. No, I got to be in the Matrix rig, which was this rig that was invented for The Matrix. I think it goes about 20 feet high, but I like to say 50 so please spread that rumor because it makes me feel cooler. I’m on this gyroscopic waist belt. It works towards your weight and makes you very nauseous. That was about the extent of my stunts for this, but we did some test pilot training too which was really fun.

Q: Can you describe the style of your character and her fashion choices?

Blake Lively: Ngila (Dickson) was very specific to make her relevant but not too modern. We didn’t want to connect the movie to any specific time. You don’t want to date it, so this is a very classic column dress which is an iconic, strong, businesswoman look.

Q: Peter, your wife dated Batman. Was it fun to also be a part of a big comic book franchise like this?

Peter Sarsgaard: My wife indeed dated Batman. Yeah, I guess it was my turn. Although I don’t get much kissing. I might get a kiss in.

Q: Can you tell us about your character?

Peter Sarsgaard: He is a biologist. He teaches at the university but his private time is quite interesting in extremophiles, animals that live in extreme environments on earth as a way to understand creatures that live on other planets. There’s a fine line there between science and wishful thinking. I thought about a lot of people who have sort of stretched our ideas and added a little bit of creativity to science like Carl Sagan or Isaac Asimov. There’s a part of me that when I was young read more things like that than I did straight comics. There’s a sense of wonder about the world where you start filling in gaps, which is what most scientists try not to do. So I really thought of him as kind of a dreamer in a lot of ways.

Q: Ryan, can you talk about playing characters in both the Marvel and DC Universes?

Ryan Reynolds: I don’t personally delineate too much between Marvel and DC and don’t pay any heed to that supposed rivalry. We live in a world in which the technology has allowed us to bring these kinds of movies to life in ways that they couldn’t two or three years ago. The emergence of the superhero franchise being so mainstream now I think is a result of that and nothing really more. I’ve never really had that thought or issue about thinking, “I was in a Marvel film so I can’t be in a DC film.”

Q: What was the casting process like?

Ryan Reynolds: The casting process for me was the same as it would have been for anyone else. I met with Martin. I fell in love with the concept and the idea. He showed me the art department, which was incredible. It was an experience. I didn’t go to the art department and see a few things, I had an experience there. To see the world they were creating for this character and this film was unlike anything I’d ever seen captured on film ever. That was an amazing moment for me. That’s what really made me want to do it. Then I screen tested for it not once, but twice. I got up there and Martin put me through the paces. But the great thing about a screen test is that it’s just another day of work. You’re there on set and there’s another actor with you. There’s a set and a cameraman. You just go to work and it was a nice, pleasant experience.

Q: How many auditions did you go through?

Martin Campbell: Well, we did test a few actors. There were a number. We tested a few of them twice. We went to England and tested a few people. Really, it’s a very serious consideration. This is not just one film but, if it’s successful, we’ll do a sequel, so we hope this is something that goes on for a long period of time. Everyone was good. Ryan was exceptional. That process is pretty standard for films like this one with so much riding on a potential franchise.

Donald De Line: We found out they always want to see the guy in the mask as part of the test. Ryan looks really good in a mask.

Ryan Reynolds: I actually have one little anecdote I wanted to add to this that I haven’t mentioned yet. There was a Cinderella element to it, because the FX house had this thing in our industry called life casts. It’s a mold of an actor’s head and you can build a mold of a prosthetic around that. You can do anything. Obviously, Peter had one done to wear his prosthetics in the film. The FX house that was asked to make the Green Lantern mask had no idea who was auditioning, but they arbitrarily chose my head from their vast catalogs of actors’ heads with which to build this mask around. So when I showed up to set, my mask fit a little better than maybe Regis Philbin’s or Richard Chamberlain’s or whoever else might have been auditioning that day.

Q: Green Lantern is pretty fearless. What’s the biggest fear you grapple with in real life?

Ryan Reynolds: What scares me? Stepping out at Comic Con in front of 6,500 people is not a settling experience. In terms of fear, I try not to live in fear. Nerves are a nice thing. They let you know you’re alive. I pay more attention to the nerves than I do the fear.

Blake Lively: I don’t want to talk about what scares me.

Q: Because many of the secondary characters are CGI, have you already cast the voices? Do you have a Kilowog?

Martin Campbell: It’s interesting. We’ve got some ideas we can’t disclose at the moment, only because of post production. We’re a year out from releasing and also the look of the characters. I’m sure there will be three or four voices tried for each character to see how they fit. You’re never quite sure until you cut the film of precisely how the characters turned out. Rather like screen tests for actors, we try voices to see what suits.

Q: Mark, can you talk about how you prepared to play Sinestro?

Mark Strong: I’m not sure you prepare for villains necessarily. You prepare for a character. I suppose the way I look at villains is that nobody is born evil. Usually something happens to their time on the planet or in space that causes them to become the way they are. You have to look at who he is and what he stands for and what he believes in. He is an incredibly organized, fearless exponent of the Green Lantern Corps who believes that he knows best. In this movie as it stands, he becomes mentor to the newly minted human Green Lantern and basically guides him through his first steps. We deal with that process, so I don’t think of him as a villain or even in a bad sense. He’s just an incredibly powerful presence who knows what he believes and what he wants to be right. If there’s anything that causes him later on to spill over to the dark side, it’s his unquestioning belief in his own rightness.

Q: Mark do you get to do the same kind of beatdown you got in Kick-Ass?

Mark Strong: Interestingly, going to work beating up a 12-year-old girl wasn’t an experience I have very often, so it’s nice to be facing a worthy opponent.

Ryan Reynolds: I’ll take that as a compliment!

Q: Do you guys get a lot of one on one time?

Mark Strong: Yeah, we’ve been training. Part of the storyline is that Hal visits Oa and Sinestro tests him because he’s not entirely sure that humans should be members of the Corps. So there’s a sequence where Kilowog and Sinestro put him through his paces.

Q: There’s a lot of talk about building to a bigger DC Universe on film. How did this affect the development of this film?

Martin Campbell: No, I don’t think that affects it at all. I think we stand absolutely on our own and we stand as our own superhero, our own story. And a terrific story it is.

Q: Ryan, how do you react when fans ask very, very specific questions about elements from, say, a certain issue of the comic book series?

Ryan Reynolds: Artful deflection. I would never profess to be as well versed or as literate in that comic book world as they are. I do know a bit about certain comic books and I’ll be the first to tell them when I don’t know about that particular issue.